The present invention relates to the field of beverage dispensing systems which utilize soluble food ingredients. More particularly, the present invention relates to a dosing device for accurate dosing of a powder.
A beverage dispenser according to the invention is a device that prepares a beverage from one or more beverage ingredients by having the ingredients interact with a liquid. In some types of beverage dispensers, beverage sources that include concentrates and/or powders are mixed with a liquid, such as water for example, in order to prepare a beverage. Thereby, in particular in the field of hot beverages such as coffee, tea or hot chocolate, powders are used for the preparation of the beverage.
The known beverage dispensers therefore comprise a dosing device for dosing a predefined amount of soluble powder stored in a storage chamber into a mixing chamber or into a dedicated vessel. Therein, liquid can be introduced in order to interact with the soluble powder and hence, form a food composition.
A known problem with such a dosing device is the accurate dosing of the powder since powder may form loose and/or hard clumps, cliff building, bridges, or triangular or pyramidal piles within the storage chamber which have a significant influence on the powder supply and dosing operation of the device. This problem occurs even more frequently in regions with high humidity since moisture supports the agglomeration of the powder. Accordingly, powder can remain caught inside the storing chamber and then does not freely flow into the dosing means.
Therefore, vibrating devices have been developed for improving the dosing operation of powdered material from a supply or storage chamber. However, powder tends to get compacted by the vibration exerted thereon.
U.S. Pat. No. 5,381,967 teaches a hopper which is vibrated in order to dispense a beverage powder. The disclosed apparatus comprises a flexible body and an actuating mechanism coupled therewith to impart motion to the flexible body at a frequency sufficient low to correspond to a non-vibrating mode.
EP 560 064 describes a dosing device cooperating with a spring placed inside a powder storing tank so that during rotation of the dosing device, the spring induces a reciprocating movement to the powder inside the powder storing tank.
U.S. Pat. Nos. 2,123,318, 2,141,815 and US 2007/0044665 also describe dosing device cooperating with respectively a spring, a resilient yoke and a vibrating arm that are put under tension and then suddenly released for providing vibration through the powder.
In the above prior art, the means for vibrating the powder are placed inside the powder tank. Then these means can induce hygienic problems, require cleaning—especially if the dosing device has not worked during a long time—and are not easily accessible for the beverage dispenser operator.
Based on the prior art, an apparatus is sought-after which improves the evacuation of powder from a dedicated container or storage chamber. Moreover, with respect to the consistency of the food product to be prepared, an apparatus is sought-after which improves the accurate dosing of a soluble powder.
It is a further aim of the invention to provide a cost-saving embodiment of low complexity which enables an evacuation of powder from a dedicated container without the need of an additional motor.
Moreover, in order to enable a broad application area of the device, a solution is sought-after which is not overly noisy.
Lastly, an aim of the invention is to provide an apparatus which minimises hygienic issues and provides the operator with an easy handling either for cleaning or repairing.
The present invention seeks to address the above described problems.